Tillage shanks are sometimes provided with a delivery tube for the purpose of placing fertilizer or other substance below the surface of the ground at the same time the moving shank is cutting through and working the soil. Some commercially available shank assemblies include a tube that has been permanently welded to the shank at a fixed location. In other situations, the farmer may obtain tubes separately from the shanks and then weld the tubes to the shanks.
A problem with the welded-on design is that if the farmer desires to apply fertilizer at different depths in varying conditions, he must change the depth of the shank as well, whether changing the shank depth is optimum for the situation at hand or not. Some commercially available conventional units provide fertilizer tubes that can be adjusted relative to the shank, but such adjustments are difficult to make and time-consuming.
Accordingly, an important object of the present invention is to provide a way of quickly and conveniently adjusting the depth of the one or more delivery tubes relative to the shank which carries it. Another important object of the invention is to provide the desired convenience and speed of adjustment while maintaining the one or more fertilizer tubes in protected positions on the shank so as to minimize abrasive wear on the tube as the shank assembly moves through the soil.
A further important object of the invention is to accomplish a way of adjustably mounting one or more tubes on the shank without exposing fastening devices to wear as the shank assembly moves through the soil.